docs(Misc): Fix awkward indentation of #include_code snippets

[iAmMichaelConnor]

From user feedback.
Whitespace is being trimmed from the start of the first line of the code snippet.
Also, code which is nested (indented) in the source code results in a code snippet where all of the code is indented. This is likely too painful to fix, and so might not be worth the effort. But flagging it in case someone wants to have a timeboxed go at it.